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ninaandphil · 22nd October 2014, 17:31

Hi, just had my MG ZT light switches converted to Blue LEDs... trouble is that now I have the switch back ( and this is the 2nd converted replacement for the original )... there is only 1 LED lit, which is on the headlight level rotor... In addition, as soon as you turn the switch for the headlights on, the whole instrument cluster and AC unit dim to virtually nothing and my CD / SAT NAV brightness fluctuates constantly. The dash dimming rotary control does not work, nor does the headlight level rotor.
I only sent of the switch facia for conversion, the main box remained in the car.
Has anyone come across this problem before, I don't want to buy another switch control box unless I'm sure the existing one is at fault... I am wondering if there is an ECU type problem communicating with the light switch pack?
All suggestions gratefully received,
Thanks
Phil

Thanks to all who responded, finally traced fault tonight. Turned out that one of the links on the ribbon cable between the PCB and the headlight switch was broken. I had the circuit board out of its housing and saw what looked like a mark on the outer edge of the ribbon about 10mm from the PCB. Looked at it with a magnifier ( I am a bit old! ) and found a break. Pared back a little of the plastic on either side and put in a bit of wire to bridge the break and bingo ....everything fine again...
Very simple, but it's taken ages to find it!

22nd October 2014, 17:31	#1
ninaandphil Avid contributor MG ZT CDTi Join Date: May 2013 Location: Exford Posts: 173 Thanks: 49 Thanked 25 Times in 20 Posts	Problem with light switch??? Hi, just had my MG ZT light switches converted to Blue LEDs... trouble is that now I have the switch back ( and this is the 2nd converted replacement for the original )... there is only 1 LED lit, which is on the headlight level rotor... In addition, as soon as you turn the switch for the headlights on, the whole instrument cluster and AC unit dim to virtually nothing and my CD / SAT NAV brightness fluctuates constantly. The dash dimming rotary control does not work, nor does the headlight level rotor. I only sent of the switch facia for conversion, the main box remained in the car. Has anyone come across this problem before, I don't want to buy another switch control box unless I'm sure the existing one is at fault... I am wondering if there is an ECU type problem communicating with the light switch pack? All suggestions gratefully received, Thanks Phil Thanks to all who responded, finally traced fault tonight. Turned out that one of the links on the ribbon cable between the PCB and the headlight switch was broken. I had the circuit board out of its housing and saw what looked like a mark on the outer edge of the ribbon about 10mm from the PCB. Looked at it with a magnifier ( I am a bit old! ) and found a break. Pared back a little of the plastic on either side and put in a bit of wire to bridge the break and bingo ....everything fine again... Very simple, but it's taken ages to find it! Last edited by ninaandphil; 24th October 2014 at 18:42.. Reason: Problem solved!